TREASURE OF KHAN. (Clive Cussler)

Genghis Khan -- the greatest conqueror of all time, who at his peak ruled an empire four times the size of Alexander the Great's, a vast expanse which stretched from the Pacific Ocean to the Caspian Sea. And now somebody wants it back. Dirk Pitt and the NUMA crew are about to come head to head with their most dangerous ever enemy. A mysterious Mongolian mogul harbors a dream of restoring the conquests of ancient Mongolia. He holds a dark secret about Genghis Khan, his grandson Kublai Khan and the treasures of Xanadu - treasures of gold, yes, but also much, much more. His relentless pursuit of them will cause devastation to millions...unless Dirk Pitt can somehow find a way to stop him.